blastFOAM: An Open-Source Computational Solver for Simulating Detonations of Energetic Materials

The ability to simulate highly compressible flows in which multiple equations of state are used to describe a system has cross-cutting applications across industries including: defense, engineering, energy, and mining. Currently, there is a paucity of available codes which can simulate these types of flows. blastFoam is a computational fluid dynamics solver based on the opensource OpenFOAM library that aims to remedy this; by providing a high-performance parallel solver which is free, open-source, verifiable, and extensively validated. blastFoam uses a density-based method to solve the five-equation model, allowing for arbitrary combinations of equations of state (e.g., JWL, Cochran-Chan, van der Walls, stiffened and Ideal gas, and Tait), and includes Riemann solvers with high-order ODE time integration to accurately solve transient problems. This explicit formulation efficiently bypasses unnecessary pressure-based thermodynamic classes in standard OpenFOAM solvers, while still leveraging the native higher order spatial integration schemes, allowing for fully third order accurate simulations. An enhanced version of adaptiveRefineFvMesh has also been developed to include adaptive mesh refinement with dynamic load balancing in order to capture a wide range of scales at a more reasonable computational cost. Finally, a pre-processing utility which allows for automatic refinement of the initial fields has been developed to allow for high initial spatial resolution in areas of interest which can then be automatically unrefined as the simulation progresses. The unstructured nature of OpenFOAM also allows for arbitrarily complex geometries to be simulated, and when hex-only meshes are used the adaptive mesh can also be leveraged – this represents major advantage over many current codes. The presented work includes verification and validation using simple 1-D cases with varying equations of state with comparison to published results. Finally, 3-D comparisons to experimental data from recently conducted explosive tests, which include a variety of airblast phenomenologies of interest to the engineering and scientific community, are presented.